It follows the couple from their first meeting on a train in 1957 to the infamous 1963 robbery, their life on the run in Australia and Ronnie's flight to Rio with the police closing in.

The show is written by Jeff Pope, the man behind the award-winning Appropriate Adult and stars Ashes To Ashes star Danny Mays as the famous fugitive.

Ms Brent told the Radio Times: "I don't think it glorifies it. It's a very honest, warts-and-all account of what occurred."

Sheridan in a scene with Danny Mays as Ronnie Biggs

Pope, who is also executive producer of the series, added: "The programme doesn't try to say that the robbers were really lovely fellas, and it doesn't try to say that they didn't assault the train driver, Jack Mills, which they did.

"It doesn't say that we should feel that they were unfairly persecuted. So it's not an apologia for the Great Train Robbers. It's a love story."

Sheridan Smith lost her blonde hair to play Charmian Biggs

Ms Brent has praised Mays' portrayal of her ex-husband, who left her and their three sons in Australia after fleeing to Brazil where he fathered a child with another woman. She said: "His hair is a little darker and he hasn't the pale blue eyes, but he's exactly the right height, the right build and he got the mannerisms perfectly. He really nailed it."